MICRO-BIOfuels project: Development of Specialized Microbial Consortia for the Conversion of Biowaste into Hydrogen and Methane.

The MICRO-BIOfuels project, led by University of Padua (Departments of Biology and Civil, Environmental and Architectural Engineering) in collaboration with MARCOPOLO Engineering (MPE), addressed the sustainable production of biohydrogen and biomethane through the valorization of organic residues. This approach aligns with the United Nations’ 2030 Agenda and the principles of the circular economy, which emphasize resource recovery and waste minimization. The conversion of organic waste into renewable energy carriers such as biohydrogen and biomethane is increasingly recognized as a key strategy for climate change mitigation and sustainable development (Alao et al., 2024). Microbial consortia play a central role in these processes, offering metabolic diversity, resilience, and synergistic interactions that enhance bioenergy yields (Jalil & Yu, 2024). In particular, sequential anaerobic digestion—first producing hydrogen via dark fermentation, followed by methane—has emerged as a highly efficient method for maximizing energy recovery from organic substrates (Rawoof et al., 2021). Within this context, the project focused on the microbial consortium EnzyVeba, developed by MPE, previously applied in bioremediation but never characterized for bioenergy applications. EnzyVeba was characterized by 16S rRNA sequencing and physicochemical profiling, followed by Biohydrogen Potential (BHP) and Biochemical Methane Potential (BMP) assays. The consortium was enriched under varying substrates and conditions to maximize biohydrogen and biomethane yields. Further, the project focused on adapting the consortium to the utilization of Organic Fraction of Municipal Solid Waste (OFMSW) and to progressively increasing ammonium concentrations, while continuously monitoring biogas output, volatile fatty acids, and community dynamics via shotgun metagenomic sequencing. Efforts were also dedicated to the isolation and genomic characterization of hydrogen-producing strains. Final steps included establishing long-term storage and reactivation protocols for the inocula. Overall, the project demonstrated the feasibility of designing and tailoring microbial consortia for efficient conversion of diverse organic wastes into renewable energy carriers. The results provided new insights into microbial ecology in DF and AD processes and offered MPE practical tools for advancing scalable and sustainable bioenergy solutions.